Solar Cell Operation, Performance and Design Rules Utilization of - PowerPoint PPT Presentation

Solar Cell Operation, Performance and Design Rules Utilization of Band Gap Energy Week 3.3.1 Arno Smets

Design Rules Solar Cells 1. Bandgap Utilization Delicate Interplay 2. Spectral Utilization 3. Light Trapping

Design Rules Solar Cells 1. Bandgap Utilization Delicate Interplay 2. Spectral Utilization 3. Light Trapping

Design Rules Solar Cells 1. Bandgap Utilization Delicate Interplay 2. Spectral Utilization 3. Light Trapping

Design Rules Solar Cells 1. Bandgap Utilization Delicate Interplay 2. Spectral Utilization 3. Light Trapping

Band gap utilization p n   k T J     B PH V ln 1   OC   q J 0 E Fn qV oc E Fp

Band gap utilization p n   k T J     B PH V ln 1   OC   q J 0 E Fn qV oc æ ö E Fp ln G L t 0 V oc = 2 kT ç ÷ ç ÷ è ø q n i

Charge Carrier Recombination Radiative Auger SRH

Charge Carrier Recombination    1 N Shockley Read Hall 0 t æ ö ln G L t 0 V oc = 2 kT ç ÷ ç ÷ q è n i ø

Charge Carrier Recombination Radiative Auger SRH

Charge Carrier Recombination t e , Aug µ p = 1 R electron = kn 2 p kn 2 R t h , Aug µ n = 1 = kp 2 n R hole kp 2 R

Charge Carrier Recombination t e , Aug µ p = 1 R electron = kn 2 p kn 2 R t h , Aug µ n = 1 = kp 2 n R hole kp 2 R

Charge Carrier Recombination

Indirect band gap Energy phonon photon Momentum

Direct band gap Energy photon Momentum

Indirect band gap: c-Si Energy phonon photon Momentum

Direct band gap: GaAs Energy photon Momentum

Band gap utilization: .....the V oc is limited by Defect-rich absorber layer Radiative Auger SRH

Band gap utilization: .....the V oc is limited by Defect-free indirect band gap Radiative Auger SRH

Band gap utilization: .....the V oc is limited by Defect-free direct band gap Radiative Auger SRH

Diffusion Length - - - - + + + + - - - - + + + + - - - - + + + + p-doped n-doped Diffusion length: L e = D e t e < L h    L D L h h h e

Minority carrier diffusion length L d

Relation between diffusion length and typical thickness of solar cells L d

p n E Fn qV oc E Fp